I am trying to understand whether it makes any sense to assign multiple VLANs to a single IP interface. The cisco router lets me do it, but I haven't figured out whether its a valid configuration.
Tagged packets arriving with one of the configured VLANs would probably be accepted and and processed (after stripping Ethernet header and vlan tag). But for packets in the reverse direction how would the router behave? How would it know which VLAN ID to put on the packet. Would it just punt and not tag it at all?
In the configuration I'm thinking about, the packets are coming from a single IP interface (non-Cisco gear) and are being tagged according to higher layer rules.
(not cisco)10.10.10.1: ----vlan10 + vlan20------- 10.10.10.2 (cisco)
ip address 10.10.10.2 255.255.255.0
vlan-id dot1q 10
vlan-id dot1q 20
no mop enabled